1. Field of the Invention
The present invention relates generally to automotive bumpers, and in particular is concerned with a reinforced impact beam for a soft bumper assembly.
2. Description of the Related Art
Soft bumper systems for both front and rear ends of automobiles are well known. Generally, an impact beam or bar is mounted to the frame or support structure with brackets and fasteners or other suitable means. Impact beams are designed to resist deformation during impact, and reduce damage to the body and other components. Oftentimes, an energy-absorbing medium, e.g., compressible foam or collapsible cellular units, is mounted on an outer face of an impact beam to absorb energy imparted by a collision. A fascia, formed from a pliable material, is fitted over the energy-absorbing medium to provide an attractive outer cover for the bumper system.
Various profiles and cross sections are used for impact beams. Some cross sections are open due to a C-shaped beam, while others are closed via a box-shaped beam. The walls of impact beams are designed with as thin gauge materials as possible to reduce weight while still providing effective deformation resistance. In open cross-section beams, separately-formed reinforcing elements can easily be inserted and secured to provide increased resistance to the deformation of front walls of impact beams.
An example of a soft bumper system can be found in U.S. Pat. No. 4,998,761, issued to the present assignee. A C-shaped impact bar or beam is reinforced against deformation during impacts by an outwardly projecting rib and an add-on reinforcement member, preferably formed from aluminum or an alloy. While this combination has been found suitable, the use of the add-on reinforcement member increases the mass of the bumper assembly.
The art continues to seek improvements. It is desirable to provide a deformation-resistant impact beam having the least mass possible to reduce the cost of the impact beam and to enhance fuel efficiency of a vehicle. Furthermore, it is desirable to provide an economical means to reinforce an impact beam, particularly a closed cross section impact beam.